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# Copyright (C) 2006-2007 Robey Pointer <>
# Copyright (C) 2012 Olle Lundberg <>
# This file is part of paramiko.
# Paramiko is free software; you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation; either version 2.1 of the License, or (at your option)
# any later version.
# Paramiko is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
# You should have received a copy of the GNU Lesser General Public License
# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
Configuration file (aka ``ssh_config``) support.
import fnmatch
import os
import re
import shlex
import socket
class SSHConfig (object):
Representation of config information as stored in the format used by
OpenSSH. Queries can be made via `lookup`. The format is described in
OpenSSH's ``ssh_config`` man page. This class is provided primarily as a
convenience to posix users (since the OpenSSH format is a de-facto
standard on posix) but should work fine on Windows too.
.. versionadded:: 1.6
SETTINGS_REGEX = re.compile(r'(\w+)(?:\s*=\s*|\s+)(.+)')
def __init__(self):
Create a new OpenSSH config object.
self._config = []
def parse(self, file_obj):
Read an OpenSSH config from the given file object.
:param file_obj: a file-like object to read the config file from
host = {"host": ['*'], "config": {}}
for line in file_obj:
# Strip any leading or trailing whitespace from the line.
# See for more info.
line = line.strip()
if not line or line.startswith('#'):
match = re.match(self.SETTINGS_REGEX, line)
if not match:
raise Exception("Unparsable line %s" % line)
key =
value =
if key == 'host':
host = {
'host': self._get_hosts(value),
'config': {}
elif key == 'proxycommand' and value.lower() == 'none':
# Store 'none' as None; prior to 3.x, it will get stripped out
# at the end (for compatibility with issue #415). After 3.x, it
# will simply not get stripped, leaving a nice explicit marker.
host['config'][key] = None
if value.startswith('"') and value.endswith('"'):
value = value[1:-1]
# identityfile, localforward, remoteforward keys are special
# cases, since they are allowed to be specified multiple times
# and they should be tried in order of specification.
if key in ['identityfile', 'localforward', 'remoteforward']:
if key in host['config']:
host['config'][key] = [value]
elif key not in host['config']:
host['config'][key] = value
def lookup(self, hostname):
Return a dict of config options for a given hostname.
The host-matching rules of OpenSSH's ``ssh_config`` man page are used:
For each parameter, the first obtained value will be used. The
configuration files contain sections separated by ``Host``
specifications, and that section is only applied for hosts that match
one of the patterns given in the specification.
Since the first obtained value for each parameter is used, more host-
specific declarations should be given near the beginning of the file,
and general defaults at the end.
The keys in the returned dict are all normalized to lowercase (look for
``"port"``, not ``"Port"``. The values are processed according to the
rules for substitution variable expansion in ``ssh_config``.
:param str hostname: the hostname to lookup
matches = [
config for config in self._config
if self._allowed(config['host'], hostname)
ret = {}
for match in matches:
for key, value in match['config'].items():
if key not in ret:
# Create a copy of the original value,
# else it will reference the original list
# in self._config and update that value too
# when the extend() is being called.
ret[key] = value[:] if value is not None else value
elif key == 'identityfile':
ret = self._expand_variables(ret, hostname)
# TODO: remove in 3.x re #670
if 'proxycommand' in ret and ret['proxycommand'] is None:
del ret['proxycommand']
return ret
def get_hostnames(self):
Return the set of literal hostnames defined in the SSH config (both
explicit hostnames and wildcard entries).
hosts = set()
for entry in self._config:
return hosts
def _allowed(self, hosts, hostname):
match = False
for host in hosts:
if host.startswith('!') and fnmatch.fnmatch(hostname, host[1:]):
return False
elif fnmatch.fnmatch(hostname, host):
match = True
return match
def _expand_variables(self, config, hostname):
Return a dict of config options with expanded substitutions
for a given hostname.
Please refer to man ``ssh_config`` for the parameters that
are replaced.
:param dict config: the config for the hostname
:param str hostname: the hostname that the config belongs to
if 'hostname' in config:
config['hostname'] = config['hostname'].replace('%h', hostname)
config['hostname'] = hostname
if 'port' in config:
port = config['port']
port = SSH_PORT
user = os.getenv('USER')
if 'user' in config:
remoteuser = config['user']
remoteuser = user
host = socket.gethostname().split('.')[0]
fqdn = LazyFqdn(config, host)
homedir = os.path.expanduser('~')
replacements = {'controlpath':
('%h', config['hostname']),
('%l', fqdn),
('%L', host),
('%n', hostname),
('%p', port),
('%r', remoteuser),
('%u', user)
('~', homedir),
('%d', homedir),
('%h', config['hostname']),
('%l', fqdn),
('%u', user),
('%r', remoteuser)
('%h', config['hostname']),
('%p', port),
('%r', remoteuser)
for k in config:
if config[k] is None:
if k in replacements:
for find, replace in replacements[k]:
if isinstance(config[k], list):
for item in range(len(config[k])):
if find in config[k][item]:
config[k][item] = config[k][item].\
replace(find, str(replace))
if find in config[k]:
config[k] = config[k].replace(find, str(replace))
return config
def _get_hosts(self, host):
Return a list of host_names from host value.
return shlex.split(host)
except ValueError:
raise Exception("Unparsable host %s" % host)
class LazyFqdn(object):
Returns the host's fqdn on request as string.
def __init__(self, config, host=None):
self.fqdn = None
self.config = config = host
def __str__(self):
if self.fqdn is None:
# If the SSH config contains AddressFamily, use that when
# determining the local host's FQDN. Using socket.getfqdn() from
# the standard library is the most general solution, but can
# result in noticeable delays on some platforms when IPv6 is
# misconfigured or not available, as it calls getaddrinfo with no
# address family specified, so both IPv4 and IPv6 are checked.
# Handle specific option
fqdn = None
address_family = self.config.get('addressfamily', 'any').lower()
if address_family != 'any':
family = socket.AF_INET if address_family == 'inet' \
else socket.AF_INET6
results = socket.getaddrinfo(,
for res in results:
af, socktype, proto, canonname, sa = res
if canonname and '.' in canonname:
fqdn = canonname
# giaerror -> socket.getaddrinfo() can't resolve
# (which is from socket.gethostname()). Fall back to the
# getfqdn() call below.
except socket.gaierror:
# Handle 'any' / unspecified
if fqdn is None:
fqdn = socket.getfqdn()
# Cache
self.fqdn = fqdn
return self.fqdn
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